Module Name: src
Committed By: simonb
Date: Tue May 12 14:04:50 UTC 2020
Modified Files:
src/sys/arch/mips/cavium/dev: octeon_rnm.c
Log Message:
Oceton RNG/RNM driver modernisation to fit new entropy world order by
riastradh@, with some tweaks to get working in RNG mode.
XXX TODO: work out how to get raw entropy mode working.
To generate a diff of this commit:
cvs rdiff -u -r1.3 -r1.4 src/sys/arch/mips/cavium/dev/octeon_rnm.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/mips/cavium/dev/octeon_rnm.c
diff -u src/sys/arch/mips/cavium/dev/octeon_rnm.c:1.3 src/sys/arch/mips/cavium/dev/octeon_rnm.c:1.4
--- src/sys/arch/mips/cavium/dev/octeon_rnm.c:1.3 Tue May 12 10:37:10 2020
+++ src/sys/arch/mips/cavium/dev/octeon_rnm.c Tue May 12 14:04:50 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: octeon_rnm.c,v 1.3 2020/05/12 10:37:10 simonb Exp $ */
+/* $NetBSD: octeon_rnm.c,v 1.4 2020/05/12 14:04:50 simonb Exp $ */
/*
* Copyright (c) 2007 Internet Initiative Japan, Inc.
@@ -27,14 +27,13 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: octeon_rnm.c,v 1.3 2020/05/12 10:37:10 simonb Exp $");
+__KERNEL_RCSID(0, "$NetBSD: octeon_rnm.c,v 1.4 2020/05/12 14:04:50 simonb Exp $");
#include <sys/param.h>
#include <sys/device.h>
-#include <sys/systm.h>
-#include <sys/sysctl.h>
#include <sys/kernel.h>
#include <sys/rndsource.h>
+#include <sys/systm.h>
#include <mips/locore.h>
#include <mips/cavium/include/iobusvar.h>
@@ -45,26 +44,18 @@ __KERNEL_RCSID(0, "$NetBSD: octeon_rnm.c
#include <sys/bus.h>
#define RNG_DELAY_CLOCK 91
-#define RNG_DEF_BURST_COUNT 10
-
-int octeon_rnm_burst_count = RNG_DEF_BURST_COUNT;
struct octeon_rnm_softc {
- device_t sc_dev;
-
bus_space_tag_t sc_bust;
bus_space_handle_t sc_regh;
-
+ kmutex_t sc_lock;
krndsource_t sc_rndsrc; /* /dev/random source */
- struct callout sc_rngto; /* rng timeout */
- int sc_rnghz; /* rng poll time */
};
static int octeon_rnm_match(device_t, struct cfdata *, void *);
static void octeon_rnm_attach(device_t, device_t, void *);
-static void octeon_rnm_rng(void *);
-static inline uint64_t octeon_rnm_load(struct octeon_rnm_softc *);
-static inline int octeon_rnm_iobdma(struct octeon_rnm_softc *);
+static void octeon_rnm_rng(size_t, void *);
+static uint64_t octeon_rnm_load(struct octeon_rnm_softc *);
CFATTACH_DECL_NEW(octeon_rnm, sizeof(struct octeon_rnm_softc),
octeon_rnm_match, octeon_rnm_attach, NULL, NULL);
@@ -94,7 +85,6 @@ octeon_rnm_attach(device_t parent, devic
aprint_normal("\n");
- sc->sc_dev = self;
sc->sc_bust = aa->aa_bust;
if (bus_space_map(aa->aa_bust, aa->aa_unit->addr, RNM_SIZE,
0, &sc->sc_regh) != 0) {
@@ -110,48 +100,81 @@ octeon_rnm_attach(device_t parent, devic
return;
}
- bus_space_write_8(sc->sc_bust, sc->sc_regh, RNM_CTL_STATUS_OFFSET,
- RNM_CTL_STATUS_RNG_EN | RNM_CTL_STATUS_ENT_EN);
-
- if (hz >= 100)
- sc->sc_rnghz = hz / 100;
- else
- sc->sc_rnghz = 1;
-
- rnd_attach_source(&sc->sc_rndsrc, device_xname(sc->sc_dev),
- RND_TYPE_RNG, RND_FLAG_NO_ESTIMATE);
+ mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_VM);
- callout_init(&sc->sc_rngto, 0);
+#ifdef notyet
+ /*
+ * Enable the internal ring oscillator entropy source (ENT),
+ * but disable the LFSR/SHA-1 engine (RNG) so we get the raw RO
+ * samples.
+ *
+ * XXX simonb
+ * To access the raw entropy, it looks like this needs to be
+ * done through the IOBDMA. Put this in the "Too Hard For Now"
+ * basket and just use the RNG.
+ */
+ bus_space_write_8(sc->sc_bust, sc->sc_regh, RNM_CTL_STATUS_OFFSET,
+ RNM_CTL_STATUS_EXP_ENT | RNM_CTL_STATUS_ENT_EN);
- octeon_rnm_rng(sc);
+ /*
+ * Once entropy is enabled, 64 bits of raw entropy is available
+ * every 8 clock cycles. Wait a microsecond now before the
+ * random callback is called to much sure random data is
+ * available.
+ */
+ delay(1);
+#else
+ /* Enable the LFSR/SHA-1 engine (RNG). */
+ bus_space_write_8(sc->sc_bust, sc->sc_regh, RNM_CTL_STATUS_OFFSET,
+ RNM_CTL_STATUS_RNG_EN | RNM_CTL_STATUS_ENT_EN);
- aprint_normal("%s: random number generator enabled: %dhz\n",
- device_xname(sc->sc_dev), sc->sc_rnghz);
+ /*
+ * Once entropy is enabled, a 64-bit random number is available
+ * every 81 clock cycles. Wait a microsecond now before the
+ * random callback is called to much sure random data is
+ * available.
+ */
+ delay(1);
+#endif
+
+ rndsource_setcb(&sc->sc_rndsrc, octeon_rnm_rng, sc);
+ rnd_attach_source(&sc->sc_rndsrc, device_xname(self), RND_TYPE_RNG,
+ RND_FLAG_DEFAULT | RND_FLAG_HASCB);
}
static void
-octeon_rnm_rng(void *vsc)
+octeon_rnm_rng(size_t nbytes, void *vsc)
{
struct octeon_rnm_softc *sc = vsc;
uint64_t rn;
int i;
- for (i = 0; i < octeon_rnm_burst_count; i++) {
+ /* Prevent concurrent access from emptying the FIFO. */
+ mutex_enter(&sc->sc_lock);
+ for (i = 0; i < howmany(nbytes, sizeof(rn)); i++) {
rn = octeon_rnm_load(sc);
rnd_add_data(&sc->sc_rndsrc,
&rn, sizeof(rn), sizeof(rn) * NBBY);
/*
* XXX
- * delay should be over RNG_DELAY_CLOCK cycles at least,
- * we need nanodelay() or clkdelay().
+ *
+ * If accessing RNG data, the 512 byte FIFO that gets
+ * 8 bytes of RNG data added every 81 clock cycles.
+ *
+ * If accessing raw oscillator entropy, the 512 byte
+ * FIFO gets 8 bytes of raw entropy added every 8 clock
+ * cycles.
+ *
+ * We should in theory rate limit calls to
+ * octeon_rnm_load() to observe this limit. In practice
+ * we don't appear to call octeon_rnm_load() anywhere
+ * near that often.
*/
- delay(1);
}
-
- callout_reset(&sc->sc_rngto, sc->sc_rnghz, octeon_rnm_rng, sc);
+ mutex_exit(&sc->sc_lock);
}
-static inline uint64_t
+static uint64_t
octeon_rnm_load(struct octeon_rnm_softc *sc)
{
uint64_t addr =
@@ -161,45 +184,3 @@ octeon_rnm_load(struct octeon_rnm_softc
return octeon_xkphys_read_8(addr);
}
-
-static inline int
-octeon_rnm_iobdma(struct octeon_rnm_softc *sc)
-{
-
- /* XXX */
- return 0;
-}
-
-SYSCTL_SETUP(octeon_rnm_sysctl, "sysctl octeon_rnm subtree setup")
-{
- int rc, root_num;
- const struct sysctlnode *node;
-
- if ( (rc = sysctl_createv(clog, 0, NULL, NULL,
- CTLFLAG_PERMANENT, CTLTYPE_NODE, "hw", NULL,
- NULL, 0, NULL, 0, CTL_HW, CTL_EOL)) != 0) {
- goto err;
- }
-
- if ( (rc = sysctl_createv(clog, 0, NULL, &node,
- CTLFLAG_PERMANENT, CTLTYPE_NODE, "octeon_rnm",
- SYSCTL_DESCR("octeon_rnm controls"),
- NULL, 0, NULL, 0, CTL_HW, CTL_CREATE, CTL_EOL)) != 0) {
- goto err;
- }
-
- root_num = node->sysctl_num;
-
- if ( (rc = sysctl_createv(clog, 0, NULL, NULL,
- CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
- CTLTYPE_INT, "burst_count",
- SYSCTL_DESCR("Burst read count per callout"),
- NULL, 0, &octeon_rnm_burst_count,
- 0, CTL_HW, root_num, CTL_CREATE, CTL_EOL)) != 0) {
- goto err;
- }
-
- return;
-err:
- printf("%s: sysctl_createv failed (rc = %d)\n", __func__, rc);
-}
